Transcription activation of IFN-beta gene. Molecular model of an enhanceosome containing the transcription factors IRF-3, ATF-2 and c-Jun bound to the interferon-beta (IFN-beta) enhancer on a strand of DNA (deoxyribonucleic acid, red and blue). Activation of the IFN-beta gene requires assembly of an enhanceosome containing a number of transcription factors including the ones shown here. These factors bind to the relevant site on the DNA strand and activate expression of the IFN-beta gene.